Many wireless devices are designed to operate in multiple frequency bands, thus increasing the versatility of such devices in different operating environments. For example, some so-called multi-band cell phones can operate in the 700-960 MHz, 1700-220 MHz and 2500-2700 MHz frequency bands, making such phones well-suited for travel between countries in which different communication standards are used. Wireless medical devices also may operate in different bands (e.g., 400 MHz, 900 MHz and 2.4 GHz bands). One drawback to such devices, however, is that an increased number of frequency bands causes impedance mismatches that ultimately result in poorer operational efficiency within each of those frequency bands. Compounding such inefficiency is the reduced power transfer that occurs between transceivers and antennas when antenna impedance varies due to environmental changes (e.g., by holding a cell phone near the head, by mounting a wireless medical device on or near a human body).